function pos = plotLink(pos_1,pos_2)
global uLINK
pos_link1 = uLINK(pos_1).p;
pos_link2 = uLINK(pos_2).p;
pos = plot3(...
    [pos_link1(1,1),pos_link2(1,1)],...
    [pos_link1(2,1),pos_link2(2,1)],...
    [pos_link1(3,1),pos_link2(3,1)]);
xlabel('x'),ylabel('y'),zlabel('z');
grid on;axis([-1 1 -1 1 -1 1]);
view([0 -1 0]);
hold on;
end